(i) Technical Field
The present invention relates to an image processing device and method, and to a non-transitory computer readable medium.
(ii) Related Art
There are image processing devices that convert data generated by an image reading device such as a scanner (data in a device-dependent color space) to data in a device-independent color space. Conversion information for performing such conversion is generated as follows. First, multiple items of data in a device-dependent color space are generated by reading multiple color patches with an image reading device, and multiple items of data in a device-independent color space are generated by performing colorimetry of the color patches. On the basis of the multiple items of data in a device-dependent color space and the multiple items of data in a device-independent color space, conversion information for converting data in a device-dependent color space to data in a device-independent color space is generated.
By the way, in the case where a color patch for generating conversion information includes a black component (K color component), data in a device-dependent color space generated by reading that color patch (such as RGB data) does not necessarily have a one-to-one correspondence with data in a device-independent color space of that color patch (such as Lab data), and the accuracy of conversion information generated using such RGB data and Lab data is lowered. As a result, the accuracy of conversion from RGB data to Lab data is lowered.
Lowering of the accuracy of conversion information is described here. For example, in the case where a color patch is formed using cyan (C), magenta (M), yellow (Y), and black (K) as color materials, even if the amounts of CMY color components are changed, a color patch in the same color (color with the same Lab values) is generated by changing the amount of a K color component. That is, there are different items of CMYK data with the same Lab values. Therefore, in the case where multiple color patches are formed by changing the amounts of CMYK color components, these color patches may include color patches in the same color but with different combinations of CMYK. When these color patches are read to generate RGB data, different items of RGB data with the same Lab values are generated. In this manner, RGB data generated by reading a color patch including a K color component does not always have a one-to-one correspondence with Lab data of that color patch, and there are different items of RGB data with the same Lab values. When conversion information is generated using such RGB data and Lab data, the accuracy thereof is lowered. In this manner, the accuracy of conversion information is lowered in a color gamut including a K color component, and the accuracy of data conversion using that conversion information is lowered. Although the circumstances arising from a K color component have been described above, the same or similar circumstances may arise from other specific color components.